Methods and devices for filtering tobacco smoke



April 1962 w. L. MINTO 3,028,864

METHODS AND DEVICES FOR FILTERING TOBACCO SMOKE Filed April '7, 1959 INVENTOR 1467;44:2- L. M/N 7'0 ATTORNEY United States Patent Ofifice 3,028,864 Patented Apr. 10, 1962 The present invention relates to a discovery and means to render more pleasant tasting and more acceptable physiologically smoke for human consumption derived from the oxidation of tobacco (usually in the form of cigarettes, cigars and pipe tobacco).

The discovery is here disclosed that deleterious eifects of smoke, and in particular the unpleasant or acrid or choking sensations derived therefrom, on the one hand, and the rise in blood pressure and the failure to remove particles from the pulmonary system on the other, are due in large measure, if not entirely, to the presence in such smoke of positive ions and the correlative discovery that with the removal of such positive ions (as, for ex ample, by their neutralization) such eflects disappear while, if in addition enough of the positive ions are neutralized so as to convert the net charge of the smoke plasma to a negative net charge, there is a noticeable loss of bite without an appreciable diiference in flavor.

The fact that cigarette smoke consists of a mixture of ions and electrically charged particles has, of course, been known for some time. Apparently, however, no one has correlated the presence of positive ions and positive elecwhich operate to remove foreign objects and substances therefrom. Thus, when the tars and other possibly toxic material in cigarette smoke enter the trachea and other branches of the pulmonary system they themselves are charged positively and along with other positively charged particles disable the cilia and thereby operate to prevent their own removal from. the body and therefore prolong and extend their toxic effects.

It is, therefore, a primary object of the present invention to provide a method for treating toxic smoke so as to prevent its irritating effects upon the pulmonary system and so as to minimize or completely neutralize its eliect upon various physiological parameters of the user.

It is a further object thereof to provide simple devices which incorporate such method.

The preferred method of treating cigarette smoke consists of either neutralizing positive ions and positively charged particles in the smoke as by bringing them into contact with sources of negative charges or ions, or to further charge such smoke negatively as by neutralizing suflicient of said positively charged ions as to bring about a net negative charge in said smoke.

Devices which may practice such method include filters which contain electrically conductive filter elements connected to ground so as to neutralize such of the positive ions or positively charged smoke as may come in contact with it, filters which themselves generate a negative charge so as to neutralize and possibly negatively charge said smoke stream, filters which are connected to an external source of negative charge relative to ground as, for example, batteries or an electric generator, and filters which are electrically connected to the coal (active burning site) of the cigarette to draw electrons therefrom.

Other objects and a fuller understanding of the present invention may be had by referring to the following detailed description and claims, taken in conjunction with the accompanying drawings which illustrate preferred embodiments thereof, it being understood that the foregoing statement of the objects of the invention and the brief summary thereof are intended to generally explain the same without limiting it in any manner.

FIG. 1 is a perspective view of an experimental filter which practices the present invention, the electric circuitry being shown schematically.

FIG. 2 is a view in perspective of a cigarette embodying'the present invention between a smokers lips.

FIG. 3 is an enlarged perspective View of the filter end of such cigarette.

FIG. 4 is an elevational view partially in section of a cigarette embodying another form of the present invention.

FIG. 5 is an elevational view of a cigarette embodying still another form of the present invention, the electrical connections being shown schematically.

FIG. 6 is a perspective view of yet another embodiment thereof.

FIG. 7 is a perspective view of a cigarette and cigar holder embodying still another form of the present invention.

FIG. 8 is a sectional view taken through the mouth engaging sleeve of the form of FIG. 7 showing the filter tubes.

Example I In order to test the efiicacy of the method here described, an experimental cigarette holder as illustrated in FIG. 1 was constructed. The same consisted of a glass tube It} approximately 10 cm. in length and having an internal diameter of 20 mm. there being mounted transversely across said tube at intervals of approximately 1 cm. three brass screen 11 of appproximately 15 mesh, each of said screens being connected in common to the central arm 12 of a potentiometer 13, the resistance element 14 thereof being connected across two 30-volt batteries 15 and 16 connected in series, the positive terminal of battery 15 being connected to one end of resistance element 14 while the negative terminal of battery 16 is connected to the other end of said element, the conductor connecting said batteries also being connected to ground, thus eifectively connecting said screens to a potential source which may be varied plus or minus 30 volts with respect to ground. Ground for this purpose was a physical ground i.e. a connection to a water pipe.

The procedure was as follows:

Condition 1.--The initial blood pressure and pulse rate of the subject was determined and noted.

Condition 2.A lighted cigarette was inserted in the holder, the screens of which were maintained by the potentiometer at a negative potential of one or more volts to ground. The subject took three puffs on the cigarette through the holder, after which his blood pressure and pulse rate were determined andnoted.

potential of one or more volts to ground. Usually, it was not possible for the subject to take more than one puff under these conditions because of the marked physiological reaction. However, after one to three puffs, his blood pressure and pulse rate were again determined and noted.

Forty such trials were conductod. Group A consisted of twenty subjects who were either non-smokers (3) or who had not smoked for at least ten hours previously (17). Group B consisted of twenty subjects who were smokers and had smoked in normal manner up to the time of the tests.

It was found that group A subjects had an initial blood pressure range of 98 through 148 mm. Hg and pulse range of 64 through 88 counts per minute, While group B subjects had initial blood pressure range of 108-150 mm. Hg and pulse range of 66 through 90 counts per minute.

The results were as follows:

The results clearly indicate the startling effect of increasing the positive charge content of the smoke and indicate very clearly the immediate effect of neutralizing the positive charges in the smoke. The significant absence of physiological effect after such neutralization appears in sharp contrast to the almost immediate physiological eifcct which is apparent upon taking into the mouth, let alone inhaling, the usual positively charged smoke from a cigarette or other tobacco burning article.

In achieving the above results non-smokers were cautioned not to inhale because of the possible vascular damage. They merely took one puff and held it in their mouths for five seconds before blowing it out. This alone produced the same rise in pulse and blood rate as the partial inhalation of the smokers. Even most smokers were unable to inhale the positively charged smoke before bursting into paroxysms of coughing.

It will be observed that in conditions 3 and 2, when the smoke was respectively neutralized and charged negatively, the alteration in physiological parameter was substantially nil, and in the latter case the smoke developed a keen and clean taste. On the other hand, smoking with the ungrounded brass screens 11 gave the usual physiological changes resulting from tobacco smoke while the development of a smoke having increased positive charges caused a choking, unbearable and unacceptable smoke with a very substantially unfavorable physiological impact.

Example II The filters were removed from a number of conventional filter cigarettes and were replaced with the construction shown in FIG. 2, using a roll of corrugated aluminum foil in the filter cavity, which was electrically connected to a copper foil tip on the cigarette.

Five persons smoked these cigarettes after having refrained from smoking for 8 or more hours. Blood pressures and pulse rates taken before, during and after smoking these cigarettes showed no significant differences. After each such determination, the subject thereupon smoked one of the conventional cigarettes, which were identical in every way except that they employed the original cellulose type filter. Smoking the conventional filter cigarette produced an immediate rise in blood presbeats per minute. These are the average values for the five persons, but the findings were remarkably uniform, pressure increases varying only in the range 10-14 mm. Hg and pulse rates in the range of 12-18 beats per minute. These uniform increases were in contrast to the relatively wide range of base values in the five individuals, wherc original blood pressures ranged from 98 mm. to mm. Hg and pulse rates from 62 to 86 per minute.

Devices which will neutralize positive ions and positive particles in smoke may be incorporated either in the consumable item itself, e.g. in a cigar, or cigarette, or in a holder therefor, e.g. a cigarette or cigar holder or a pipe. Perhaps the simplest and most effective device is one which incorporates a conductive filter element so arranged that it intercepts the smoke before it reaches the smoker and is grounded to the smokers lips, thereby employing the smoker himself as a source of electrons.

A cigarette embodying such a filter is illustrated in FIGS. 2 and 3 wherein a cigarette 17 is positioned within the smokers lips 18, the filter section 11$ being in electrical contact with the lips and consisting generally of a roll 20 of corrugated aluminum foil which replaces the usual cellulose filter element within known cigarettes and which provides a. great many passages extending longitudinally along the path of the smoke. The free end of said roll extends through a slot 21 in a stiffened liner 22. which may be made of the same cardboard or like material as is found in commonly employed cigarette filters, so as to surround all or a portion of said liner and so as to present an electrically conductive surface to contact the users lips.

As smoke passes through the passages provided by corrugated roll 20, the positive ions and particles come in contact with the walls thereof and pick up electrons, thereby becoming neutral. The interfacial resistance for a lip ground varies widely depending upon many characteristics of the user and the degree of hydration of the surface of the lips at a given moment. In addition, lipstick or other applied material may affect such resistance. Usually such resistance will bt less than a magohm with a median of 100,000 ohms. Those who are wet-lipped present resistances down to about 1,000 ohms. In view of the fact, however, that the currents which must be passed are extremely small, being of the order of millimicroamperes, and the fact that the ions are in the 0.1-5 volts range, even an interfacial resistance of 1,000 megohms would not cause problems with the highest ion density reasonably expected in the smoke of the strongest cigar.

Manifestly the precise mechanisms involved in achieving the physiological effects readily measured upon the intake of cigarette smoke and the like are not clearly understood. It will be observed that in the embodiment of the present invention illustrated in FIGS. 2 and 3 and in some of the other embodiments thereof, the lips of the smoker are employed as a source of electrons and theoretically this should leave the lips somewhat positively charged until a charge balance is reestablished. It is theorized, however, that when positively charged smoke enters the pulmonary passages and is there neutralized as by extracting an electron from the walls or coating covering the walls thereof, irritation and the initiation of the other physiological efiects noted take place. Apparently then, the site at which electrons are drawn from the body determines whether deleterious physiological processes will be initiated. Drawing electrons from the lips apparently gives rise to no such effects, while drawing electrons from the pulmonary passages apparently does give rise to such eifects.

The filter of FIGS. 2 and 3 may be varied substantially without departing from the basic inventive concept underlying it. For example, instead of a roll of aluminum foil there may be employed any type of electrically conduc' tive material which does not deteriorate substantially or itself give off toxic matter during the life of the filter element. For example, the material may be a plurality of small tubes or solid wires or fibers arranged in parallel form or twisted or matted so that they are at randomized angles to the direction of smoke flow and so that they may present smoke paths which are either linear, irregular or follow other geometric paths such as spirals, mazes and the like in order to eifect an extension of the contact time and more intimate contact between the smoke and filter elements. The filter elements should be made of electropositive material, i.e. an electron donor as, for example, aluminum. In the event that one material is used to contact the smokers lips and another material is used as the filter element, then the material composing the filter element should be more electropositive than the material which contacts the smokers lips. If this is not the case, then the smoke may become more positively charged and hence more irritating. For example, if the filter element consisted 'of steel wool which was electrically connected to an aluminum foil tip in contact with the smokers lips, the steel wool would become positively charged'in relationto ground by reason of the difference in electric potential between the dissimilar metals, and the smoke would therefore become more irritating then it otherwise would be. On the other hand, if the filter element consists of aluminum wool 24 lying within and in electrical connection with a cylindrical tip 25 or holder consisting of a less electrically positive conductor, i.e. silver (as shown in FIG. 4), then the smoke would become even more negatively charged and it would have a smooth and clean taste.

Still another embodiment of the present invention is shown in FIG. 5 wherein the cigarette terminates in a conductive sleeve or tip 27 made of aluminum or other conducting material which is electrically connected as by a fine wire 28 to a series of alternately similar and dissimilar perforated disks or screens such as disks 2? which may be made of aluminum and disks 30 which may be made of copper or graphite. The disks become electrically charged with respect to each other. The potential difierence may be developed either by thermoelectric effects or by reason of their ionization potentials in the electrically conductive plasma of smoke, or by a combination of these effects. This form actuatlly contributes a surplus of negative ions to the smoke stream, i.e. the smoke which is emitted may bear a net negative charge.

The dissimilar disks should be so arranged that the smoke passes last over the best electron donor before reaching the smoker, i.e. the last disk should be more electro-positive than any of the others.

As an alternate form (not shown) the conductive tip may be connected to a ground which is not the smokers lips or it may be connected to an external source of negative potential. In either of these events, substitution may be made for the tip itself since then all that is needed is a connection between the filter elements and the external ground or source of negative potential.

Another form of the present invention is illustrated in FIG. 6. If the smoke originating from the burning front tip or coal (i.e. the active burning site) of a cigarette or cigar or pipeful of tobacco is positively charged, then one would expect the area of the coal to be negatively charged. Upon examination it was found that this is so. Hence it became apparent that the coal itself could be used as a source of negative charges to neutralize the positively charged smoke as it passed through the filter at the rear of the cigarette. The negative charges or electrons from the coal may be extracted and carried to the site of the filter by means of a thin wire or by means of a consumable graphite strip painted, imprinted or otherwise placed upon a cigarette wrapper or leaf tobacco, etc., or other conductor. In FIG. 6 such an arrangement is shown wherein cigarette 32 terminates in an electrically conducting rear tip 31 which is connected by a painted strip of graphite 33 to the coal 34 of the burning cigarette. As the smoker causes a draft to proceed through the cigarette and the coal burns, the smoke travelling through the cigarette is positively charged leaving the coal negatively charged. Electrons may then be drawn from the coal by means of the conducting graphite strip 33 and transmitted to the conductor tip from which they are in turn transmitted to the filter element consisting of aluminum wool or he like (not shown) within the tip, thereby neutralizing or tending to neutralize smoke passing therethrough.

Obviously the structures shown may be incorporated in a separate device, i.e a separate filter. Such a cigarette or cigar holder is shown in FIGS. 7 and 8 in which the filter element consists of a bundle of metal tubes 35 within a metal sleeve 36 which in turn may lie within a plastic sleeve 37, while a battery 38, as for example, the type used as grid bias cells, may be mounted to plastic sleeve 37 and so connected that its negative ter minal is connected to a'high resistor 39 which in turn is connected to sleeve 36 and hence is in electrical contact with tubes 35, whileit's positive terminal is connected to sleeve 36. Obviously, a'similar device'could be incorporatedin the stem of a pipe or in any other type of device adapted to conduct smoke from burning tobacco.

Of course, the filters shown may be employed along With mechanical filters of the type presently used, in which event it is recommended that such mechanical filters be placed forward in the smoke screen of the electrical filters here described so as to minimize fouling of the electrical filter elements.

It should be noted that low voltages are employed, a potential of a fraction of a volt being sufiicient so long as electrons are available to be removed by the approach of positively charged ions to the filter element surfaces. It will be noted that in the experimental work detailed above, just one or a few volts produced the physiological charges noted. This is in sharp contrast to electrostatic precipitation filters which use hundreds and usually thousands of volts to collect particles or to devices which seek to inject negative ions, which in the presence of gases at atmospheric pressure would require voltages of the order of at least 1,000 volts. The devices of the present invention are therefore low voltage devices. To give preciseness of meaning to the term as used in the claims low voltage will be understood as referring to 30 volts or less.

Although the present invention has been describer with a certain degree of particularlity, it is understood that the present disclosure has been made only by way of example and that numerous variations may be employed without transcending the scope of the invention as hereinafter claimed.

What is claimed is:

1. A filter cigarette comprising a cigarette body including a cylindrical roll of divided tobacco, a consumable wrapper about such tobacco, a filter element of electrically conducting material connected to said body at a filter end thereof and positioned in longitudinal extension of said roll, there being formed in said element a plurality of passages to permit the passage of smoke therethrough and means to feed only low voltage electrons to said element.

2. A filter cigarette as described in claim 1, said means including an electrically conducting terminal contact member positioned proximate the filter end of said body and at the periphery thereof so as to be contactable by the lips of a smoker, said contact member being electrically connected to said element.

3. A filter cigarette as described in claim 2, said element being more electro-positive than said member.

4. A filter cigarette as described in claim 1, said means including an electrical conductor, connected at one end to said filter element and extending longitudinally the length of said cigarette to the end thereof distal said filter end, whereby as said cigarette is lit and a burning coal formed said coal and element will be electrically connected.

5. A filter cigarette as described in claim 4 said conductor being consumable by said coal.

6. A smoke treatment device comprising a member having a smoke passageway formed therein and extending therethrough, tobacco holding means at one end of said member and a mouthpiece portion at the other end thereof, an electrically conducting treating element mounted to said member in said passageway and provided with a plurality of passages through which smoke may pass, means electrically connected to said element to feed only low voltage electrons of less than 30 volts to said element.

7. A device as described in claim 6, said element including fibrous material.

8. A device as described in claim 6, said element including a plurality of tubes the longitudinal axes of which lie along said passageway.

9. A device as described in claim 6, said element ineluding a roll of irregularly surfaced foil, the axis about which said roll extends lying along said passageway.

10. A device as described in claim 6, said element including a plurality of spaced electrically connected plates positioned in said smoke passageway.

11. A device as described in claim 10, the plate proximate the mouthpiece portion end of said member being more electropositive than the remainder of said plates.

12. A smoke treatment device dimensioned to be supported by a smokers mouth and lips comprising a sleeve having a smoke passageway formed therein and extending therethrough, a mouthpiece portion at a mouthpiece end of said sleeve and tobacco-holding means at the other end of said sleeve, said mouthpiece portion including an external electrically conductive portion, an electrically conducting treating element electrically connected to said conductive portion and mounted to said sleeve in said smoke passageway, there being formed in said treating element a plurality of smoke passages therethrough, said element being of a material which is an electron donor more eleetrop'ositive than the electrically conductive portion of said mouthpiece portion.

13. A device as described in claim 12, said element including fibrous material.

14. A device as described in claim 12, said element including a plurality of tubes the longitudinal axes of which lie along said passageway.

15. A device as described in claim 12, said element including a roll of irregularly surfaced foil, the axis about which said roll extends lying along said passageway.

16. A device as described in claim 12, said element including a plurality of spaced electrically connected plates positioned in said smoke passageway.

17. A device as described in claim 16, the plate proximate the mouthpiece end of said sleeve being more electropositive than the remainder of said plates.

18. A filter for tobacco smoke comprising a member having a smoke passageway formed therein and extending therethrough, tobacco holding means at one end of said member and a mouthpiece portion at the other end thereof, an electrically conducting treating element mounted to said member in said passageway, said element having formed therein a plurality of passages through which smoke may pass and a low voltage electric battery, the voltage of which lies below 30 volts, connected by its negative terminal in serial with said element.

19. A smoking article comprising an elongated charge of tobacco including a coal end and a filter end, a smoke treatment device comprising a member having a smoke passageway formed therein and extending therethrough and being mechanically connected to said tobacco charge at said filter end thereof, said member having a mouthpiece portion at the other end thereof, an electrically conducting treatment element mounted to said member in said passageway, said element having formed therein a plurality of passages through which smoke may pass, an electrical conductor connected to said element at one end and extending from said end to said coal end of said tobacco charge.

20. A filter as described in claim 19 said conductor being consumable by the coal formed as said article is smoked.

References Cited in the file of this patent UNITED STATES PATENTS 2,132,539 McRae Oct. 11, 1938 2,381,455 Jacob Aug. 7, 1945 2,594,777 Hicks Apr. 29, 1952 2,639,972 Hicks May 26, 1953 2,640,158 Hicks May 26, 1953 2,669,995 Troy Feb. 23, 1954 2,804,874 Visnick Sept. 3, 1957 2,916,038 Wade Dec. 18, 1959 2,933,151 Kurtz Apr. 19, 1960 OTHER REFERENCES Biologic Effects of Ionized Air in Man by Windor and Beckett, The American Journal of Medicine, vol. 37. No. 2, pages 83-89 (April 1958).

Effects of Gaseous Ions on Tracheal Ciliary Rate by Krueger and Smith, vol. 98 (1958), pages 412 to 414 in the Proceedings of The Society for Experimental Biology and Medicine. 

